1/* $NetBSD: flt_rounds.c,v 1.6 2022/04/08 10:17:52 andvar Exp $ */ 2 3/* 4 * Copyright (c) 1996 Mark Brinicombe 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Mark Brinicombe 18 * for the NetBSD Project. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34#include <sys/cdefs.h> 35#if defined(LIBC_SCCS) && !defined(lint) 36__RCSID("$NetBSD: flt_rounds.c,v 1.6 2022/04/08 10:17:52 andvar Exp $"); 37#endif /* LIBC_SCCS and not lint */ 38 39#include "namespace.h" 40#include <sys/types.h> 41#include <ieeefp.h> 42 43static const int map[] = { 44 1, /* round to nearest */ 45 2, /* round to positive infinity */ 46 3, /* round to negative infinity */ 47 0 /* round to zero */ 48}; 49 50/* 51 * Return the current FP rounding mode 52 * 53 * Returns: 54 * 0 - round to zero 55 * 1 - round to nearest 56 * 2 - round to positive infinity 57 * 3 - round to negative infinity 58 * 59 * ok all we need to do is get the current FP rounding mode 60 * index our map table and return the appropriate value. 61 * 62 * HOWEVER: 63 * The ARM FPA codes the rounding mode into the actual FP instructions 64 * so there is no such thing as a global rounding mode. 65 * The default is round to nearest if rounding is not explicitly specified. 66 * FP instructions generated by GCC will not explicitly specify a rounding 67 * mode. 68 * 69 * So the best we can do it to return the rounding mode FP instructions 70 * use if rounding is not specified which is round to nearest. 71 * 72 * This could change in the future with new floating point emulators or 73 * soft float FP libraries. 74 */ 75 76int __flt_rounds(void); 77 78int 79__flt_rounds(void) 80{ 81 return(map[fpgetround()]); 82} 83